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Analysis of Protein-protein Interactions and Co-localization Between Components of Gap, Tight, and Adherens Junctions in Murine Mammary Glands
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Analysis of Protein-protein Interactions and Co-localization Between Components of Gap, Tight, and Adherens Junctions in Murine Mammary Glands

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Involvement of the junctional adhesion molecule-1 (JAM1) homodimer interface in regulation of epithelial barrier

Kenneth J Mandell1, Ingrid C McCall, Charles A Parkos

  • 1Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA. kjmande@emory.edu

The Journal of Biological Chemistry
|January 30, 2004
PubMed

Insights

Junctional adhesion molecule-1 (JAM1) homodimer formation is crucial for its role in epithelial barrier function. Blocking this dimerization impairs tight junction recovery and cell adhesion.

Area of Science:

  • Cell biology
  • Structural biology
  • Immunology

Background:

  • Junctional adhesion molecule-1 (JAM1) is a protein regulating epithelial tight junctions and leukocyte transmigration.
  • The structural basis for JAM1's function, particularly homodimerization, remains unclear.

Purpose of the Study:

  • To investigate the role of JAM1 homodimer formation in epithelial cell function.
  • To determine the structural basis of JAM1's function at tight junctions.

Main Methods:

  • Utilized monoclonal antibodies to assess effects on epithelial barrier recovery.
  • Employed phage display for epitope mapping and site-directed mutagenesis.
  • Performed crystal structure analysis and in vitro dimerization assays.

Main Results:

  • Inhibitory antibodies targeting residues 111-123 blocked epithelial barrier recovery.
  • This epitope is located at the putative JAM1 homodimer interface.
  • Antibody binding and interface mutations disrupted JAM1 homodimerization and cell surface localization.

Conclusions:

  • JAM1 homodimer formation is essential for its function in epithelial barrier integrity.
  • Disruption of homodimerization impairs JAM1 localization at tight junctions.
  • Homodimerization is a key regulatory mechanism for JAM1-mediated epithelial cell adhesion.

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